3DIC packages with heat dissipation structures

ABSTRACT

A package includes a first die and a second die underlying the first die and in a same first die stack as the first die. The second die includes a first portion overlapped by the first die, and a second portion extending laterally beyond a respective edge of the first die. The package further includes a first Thermal Interface Material (TIM) over and contacting a top surface of the first die, a heat dissipating lid having a first bottom surface contacting the first TIM, a second TIM over and contacting the second portion of the second die, and a heat dissipating ring having a portion over and contacting the second TIM. The heat dissipating lid and the heat dissipating ring are discrete components, and at least one of the heat dissipating lid or the heat dissipating ring has a plurality of fins and a plurality of recesses separating the plurality of fins from each other.

PRIORITY CLAIM AND CROSS-REFERENCE

This application is a continuation of U.S. patent application Ser. No.15/172,230, entitled “3DIC Packages with Heat Dissipation Structures,”filed Jun. 3, 2016, which is a continuation of U.S. patent applicationSer. No. 14/579,388, entitled “3DIC Packages with Heat DissipationStructures,” filed Dec. 22, 2014, now U.S. Pat. No. 9,379,036, issuedJun. 28, 2016, which is a divisional of U.S. patent application Ser. No.13/957,727, entitled “3DIC Packages with Heat Dissipation Structures,”filed on Aug. 2, 2013, now U.S. Pat. No. 9,082,743, issued Jul. 14,2015, which applications are incorporated herein by reference.

BACKGROUND

In the packaging of integrated circuits, semiconductor dies may bestacked through bonding, and may be bonded to other package componentssuch as interposers and package substrates. The resulting packages areknown as Three-Dimensional Integrated Circuits (3DICs). The heatdissipation is a challenge in the 3DICs. There exists a bottleneck inefficiently dissipating the heat generated in the inner dies of the3DICs. The heat generated in the inner dies has to be dissipated toouter components such as outer dies before the heat can be conducted toany heat spreader. Between the stacked dies, however, there exist othermaterials such as underfill, molding compound, etc, which are noteffective in conducting heat. Furthermore, the stacked dies may also bemolded in a molding compound, which prevents the efficient heatdissipation.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the embodiments, and the advantagesthereof, reference is now made to the following descriptions taken inconjunction with the accompanying drawings, in which:

FIGS. 1 through 5 are cross-sectional views of intermediate stages inthe formation of a package in accordance with some exemplaryembodiments;

FIGS. 6A and 6B illustrate the floor planes of a logic die and a memorydie in accordance with some embodiments;

FIGS. 7, 8, and 9 illustrate some exemplary allocation schemes ofhigh-power-consuming circuits and the respective heat dissipating rings;

FIG. 10 illustrates a top view of a plurality of die stacks bonded to apackage component;

FIGS. 11A, 11B, and 11C illustrate the cross-sectional view, theperspective view, and a cross-section of the perspective view of apackage in accordance with some embodiments;

FIG. 12 illustrates the cross-sectional view of a package in accordancewith some embodiments, wherein the heat dissipating lid comprises arecessed portion and a protruding portion;

FIG. 13 illustrates the cross-sectional view of a package in accordancewith some embodiments, wherein a System-on-Chip die is bonded;

FIG. 14 illustrates the cross-sectional view of a package in accordancewith some embodiments, wherein a System-on-Chip die is bonded, andwherein a heat dissipating lid overlaps to contact different dies of adie stack; and

FIGS. 15A and 15B illustrate a cross-sectional view and a top view of apackage in accordance with some embodiments, wherein a heat dissipatinglid and a heat dissipating ring comprise heat sinks.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The making and using of the embodiments of the disclosure are discussedin detail below. It should be appreciated, however, that the embodimentsprovide many applicable concepts that can be embodied in a wide varietyof specific contexts. The specific embodiments discussed areillustrative, and do not limit the scope of the disclosure.

A package with improved heat dissipating ability and the method offorming the same are provided in accordance with various exemplaryembodiments. The intermediate stages of forming the package areillustrated. The variations of the embodiments are discussed. Throughoutthe various views and illustrative embodiments, like reference numbersare used to designate like elements.

FIG. 1 illustrates the cross-sectional view of an initial stage in theformation of Three-Dimensional Integrated Circuit (3DIC) package 100,which includes dies 10 stacked on die 12. In some embodiments, dies 10are memory dies that form a memory stack. In alternative embodiments,dies 10 are logic dies. In yet alternative embodiments, dies 10 includeboth logic dies and memory dies. Die 12 may be a logic die, which mayfurther be a Central Processing Unit (CPU), a Graphics Processing Unit(GPU), or the like. Dies 10 and 12 may be bonded through flip chipbonding, wherein metal bumps, solder balls, or the like are used to bonddies 10 and 12.

Die 12 has a top view size greater than the top view size of dies 10. Asshown in FIG. 1, die 12 may extend laterally beyond dies 10, and mayinclude portion 12A that is overlapped by dies 10, and portions 12B thatare not overlapped by dies 10. The die stack including dies 10 and 12are further bonded to package component 14, which may be a packagesubstrate, an interposer, a Printed Circuit Board (PCB), or the like.Discrete passive devices 17 such as resistors, capacitors, transformers,and the like, may also be bonded to package component 14. Solder balls15 are attached to package component 14, wherein dies 10/12 and solderballs 15 are on opposite sides of package component 14.

Next, referring to FIG. 2, Thermal Interface Material (TIM) 16 isdispensed on dies 10 and 12. TIM 16 includes portion 16A, which isdispensed on the top of dies 10. Furthermore, TIM 16 includes portions16B, which are also dispensed on, and may be in physical contact with,the top surfaces of portions 12B of die 12. TIM 16 has a good thermalconductivity, which may be greater than about 2 W/m*K, and may be asequal to, or higher than, about 10 W/m K or 50 W/m*K. TIM portions 16Bmay, or may not, form a ring. In accordance with some embodiments, whenforming the ring, TIM portions 16B encircle dies 10. In whichembodiments, portions 12B of die 12 also forms a ring. FIGS. 7, 8, and 9illustrate the embodiments wherein TIM portion 16B does not form a ring.

FIG. 3 illustrates the attachment of heat dissipation ring 20 to packagecomponent 14. Heat dissipation ring 20 has a high thermal conductivitygreater than about 100 W/m*K, for example, and may be formed using ametal, a metal alloy, or the like. For example, heat dissipation ring 20may comprise metals and/or metal alloys selected from the groupconsisting of Al, Cu, Ni, Co, and the like. Heat dissipation ring 20 mayalso be formed of a composite material selected from the groupconsisting of silicon carbide, aluminum nitride, graphite, and the like.Heat dissipation ring 20 includes a first bottom surface(s) 20Acontacting TIM portion 16B, and a second bottom surface(s) 20B adheredto package component 14 through adhesive 22. Adhesive 22 may have abetter adhering ability and a lower thermal conductivity than TIM 16.For example, adhesive 22 may have a thermal conductivity lower thanabout 0.5 W/m*K.

Next, referring to FIG. 4, adhesive 26 is dispensed on a top surface ofheat dissipating ring 20, and heat dissipating lid 24 is mounted. Heatdissipating lid 24 includes bottom surface 24A and bottom surface 24B.The position of bottom surfaces 24A and 24B are designed to fit theheight of the top surface of dies 10 (and TIM portion 16A) and thelocation of adhesive 26. In the illustrated exemplary embodiments,bottom surface 24A is lower than bottom surface 24B. Bottom surface 24Ais in contact with TIM portion 16A. Bottom surface is in contact withadhesive 26, which adheres heat dissipating lid 24 to heat dissipatingring 20. The top surfaces of dissipating ring 20 and heat dissipatinglid 24 may be substantially co-planar. Heat dissipation lid 24 has ahigh thermal conductivity greater than about 100 W/m*K, for example, andmay be formed using a metal, a metal alloy, or the like. For example,heat dissipation lid 24 may comprise metals and/or metal alloys selectedfrom the group consisting of Al, Cu, Ni, Co, and the like. Heatdissipation lid 24 may also be formed of a composite material selectedfrom the group consisting of silicon carbide, aluminum nitride,graphite, and the like.

FIG. 5 illustrates the mounting of heat sink 28 on heat dissipating ring20 and heat dissipating lid 24, wherein TIM 16C is dispensed over heatsink 28 and underlying dissipating ring 20 and heat dissipating lid 24.FIG. 5 illustrates the heat dissipating paths 32 (including 32A and 32B)represented by arrows. From die stacks 10/12, there are two major heatdissipating paths 32A and 32B. The heat generated in die 12 may bedissipated to heat dissipating ring 20 through heat dissipating paths32A, and further dissipated to heat sink 28 through TIM portion 16C. Theheat generated in dies 10 may be dissipated to heat dissipating lid 24through heat dissipating paths 32B, and further dissipated to heat sink28 through TIM portion 16C. Since Adhesive 26 has a low thermalconductivity, the cross-dissipation of the heat in heat dissipating ring20 and heat dissipating lid 24 is not significant, and may be ignored.

In the embodiments in FIG. 5, the heat in die 12 has its own heatdissipation path, which does not go through the overlying dies 10, asoften seen in conventional heat dissipating structures. Since die 12 maybe a logic die that consumes higher power, the heat generated by die 12,if dissipated through dies 10 (which may be memory dies), will adverselyaffect the performance and reliability of dies 10. In the embodiments ofthe present disclosure, the heat generated by die 12 does not go throughdies 10, and dies 10 are not affected.

FIGS. 6A and 6B illustrate some exemplary floor planes of dies 12 and10, respectively, which floor planes affect the customization of heatdissipating lid 24 and heat dissipating 20. For example, in FIG. 6A, die12 includes high-power-consuming circuits 34 and low-power-consumingcircuits 36 consuming less power than high-power-consuming circuits 34.The high-power-consuming circuits 34 may be Serializer/Deserializer(Serdes), and the low-power-consuming circuits may be controllers insome embodiments. Serdes 34 consumes more power, and hence generatesmore heat, than controllers 36. In accordance with some embodiments,Serdes 34 (or other high-power circuits) are at least partially, andpossibly in entirety, allocated in portions 12B of die 12, whichportions 12B are not overlapped by dies 10, as shown in FIG. 5. On theother hand, controllers 36 (or other low-power circuits) are at leastpartially, and possibly entirely, allocated in portion 12A of die 12,which portion 12A is overlapped by dies 10, as shown in FIG. 5. FIG. 6Bschematically illustrates an exemplary floor plane of die 10, which is amemory die in these embodiments. Memory die 10 may include a pluralityof memory storage banks 38 distributed throughout die 10.

As shown in FIG. 5, by overlapping heat dissipating ring 20 with dieportions 12B that have high-power-consuming circuits, the heat generatedin the high-power-consuming circuits may be dissipated to heatdissipating ring 20 directly without going through dies 10. The heatdissipating efficiency is thus improved.

FIGS. 7, 8, and 9 illustrate some examples wherein thehigh-power-consuming circuits 34 are distributed to different parts ofdie 12, and the respective schemes for designing heat dissipating ring20. Each of FIGS. 7, 8, and 9 illustrates a top view of dies 10, die 12,and a portion of heat dissipating ring 20. Although heat dissipatingring 20 may form a ring, for clarity, only the portion of heatdissipating ring 20 close to high-power-consuming circuits 34 areillustrated, while other parts are not shown. Referring to FIG. 7,high-power-consuming circuit 34 is distributed at the left bottom cornerof the illustrated die 12, wherein portion 34A of high-power-consumingcircuit 34 is overlapped by dies 12 (through TIM 16B, refer to FIG. 5),and portion 34B of high-power-consuming circuit 34 is not overlapped bydies 10. Heat dissipating ring 20 includes an arm extend to overlapportion 34B of high-power-consuming circuit 34. It is to be appreciatedthat although FIGS. 7, 8, and 9 illustrate that heat dissipation ring 20extends to overlap high-power-consuming circuits 34 of die 12, heatdissipation ring 20 may also extend to overlap low-power-consumingcircuits 36 (FIG. 5) of die 12, and the overlapped portions of heatdissipation ring 20 and die 12 forms a ring.

FIG. 8 illustrates the top view of a package in accordance withalternative embodiments. In these embodiments, two high-power-consumingcircuits 34 are allocated to close to two edges of die 12. Accordingly,heat dissipating ring 20 includes two arms, each extending to overlapone of high-power-consuming circuits 34. In FIG. 9, onehigh-power-consuming circuit 34 is close to the left edge of die 12, andthe other high-power-consuming circuit 34 is close to the right bottomcorner of die 12. Accordingly, heat dissipating ring 20 includes anextension bar overlapping the high-power-consuming circuit 34 at theleft edge, and an extension arm overlapping the right bottom corner ofdie 12.

FIGS. 10 through 11C illustrate the heat dissipation scheme inaccordance with alternative embodiments. FIG. 10 illustrates a pluralityof die stacks 10/12 bonded to package component 14. In the illustratedexamples, there are four die stacks 10/12. FIG. 11A illustrates across-sectional view of the respective package. As shown in FIG. 11A,die stacks 10/12 may have heights H1 and H2, which may be equal to eachother or different from each other. Accordingly, heat dissipating lid 24comprises a plurality of portions 24′ extending down to different levelsto compensate for the height difference of die stacks 10/12. Theplurality of portions 24′ are in contact with TIM portions 16A.

FIGS. 11B and 11C illustrate the perspective view and a cross-section ofthe perspective view, respectively, of the package before assembled. Asshown in FIG. 11B, heat dissipating ring 20 may comprise a plurality ofextensions 20C extending into the spaces between die stacks 10/12 (FIG.10). In the illustrated example, the extensions 20C form a cross,wherein the cross is inside a part of heat dissipating ring 20 thatforms a rectangular frame. The ends of cross 20C are connected to therectangular frame so that heat dissipating ring 20 forms an integratedunit. Accordingly, in the top view of heat dissipating ring 20, heatdissipating ring 20 includes four openings. Heat dissipating lid 24includes thin portions that are to be supported by heat dissipating ring20. Heat dissipating lid 24 also includes portions 24′ that extend intothe openings in heat dissipating ring 20.

FIG. 12 illustrates the heat dissipation scheme in accordance with yetalternative embodiments. Package 100 in these embodiments is similar tothe embodiments in FIG. 11A, except package 100 in these embodimentsinclude a high die stack 10/12, and a System-on-Chip (SoC) die 40 with asmaller height. There is a significant height difference between diestacks 10/12 and die 40. To accommodate for the height difference, heatdissipating lid 24 includes recess 24″, wherein the recessed portion hasthickness T1. Die stack 10/12 extends into recess 24″. Heat dissipatinglid 24 also includes protruding portion 24′, wherein the protrudingportion has thickness T2. As shown in FIG. 12, the recessed portion andthe protruded portion of heat dissipating lid 24 have differentthicknesses T1 and T2, respectively, which are selected to compensatefor the height difference between die stacks 10/12 and SoC die 40. Inthese embodiments, the heat in dies 10 and SoC die 40 are dissipated tothe same heat dissipating lid 24.

FIG. 13 illustrates the heat dissipation scheme in accordance with yetalternative embodiments. These embodiments differ from the embodimentsin FIG. 12 in that the SoC die 40 in these embodiments consumes morepower than in the embodiments in FIG. 12. Accordingly, the top of SoCdie 40 is adhered to heat dissipating ring 20D (through TIM 16) insteadof heat dissipating lid 24, so that the heat in dies 10 and die 40 aredissipated through different heat-dissipating components. Portion 12B ofdie 12 is adhered to heat dissipating ring 20E (through TIM 16).Accordingly, in these embodiments, the heat in dies 10 is dissipated toheat dissipating lid 24, while the heat in SoC die 40 is dissipated todissipating ring 20D. In some embodiments, heat dissipating rings 20Dand 20E are separate heat dissipating components physically disconnectedfrom each other. In alternative embodiments, heat dissipating rings 20Dand 20E, although appear to be disconnected in the cross-sectional view,are parts of the same integrated heat dissipating ring. The areas ofheat dissipating ring 20D may be increased to improve the heatdissipating ability.

FIG. 14 illustrates the heat dissipation scheme in accordance with yetalternative embodiments. These embodiments differ from the embodimentsin FIG. 13 in that heat dissipating lid 24 includes a recessed portionfor die stacks 10/12 to extend in, and protruding portions to adhere toportions 12B of die 12. Accordingly, the heat generated in die portions12B and dies 10 are dissipated to the same heat dissipating lid 24. Onthe other hand, heat dissipating ring 20 comprises a bottom surfaceadhered to SoC die 40 through TIM 16, so that the heat generated in SoCdie 40 is dissipated to heat dissipating ring 20.

FIGS. 15A and 15B illustrate the heat dissipation scheme in accordancewith yet alternative embodiments. These embodiments are similar to theembodiments in FIG. 5, except that heat dissipating ring 20 and/or heatdissipating lid 24 are heat sinks comprising fins and recessesseparating the fins. With the fins, the heat dissipating ability of heatdissipating ring 20 and/or heat dissipating lid 24 is improved due toincreased surface. FIG. 15A illustrates a cross-sectional view. In someembodiments, heat dissipating ring 20 includes portions extending beyondthe edges of package component 14 to increase the heat dissipatingability. FIG. 15B illustrates a top view, wherein the top view isobtained at the level A-A in FIG. 15A. FIG. 15B illustrates that heatdissipating ring 20 encircles heat dissipating lid 24 and dies 10.

By using both heat dissipating ring 20 and heat dissipating lid 24, theheat in packages may be dissipated more efficiently. A simulation isperformed to simulate the temperature distribution in the in packagescomprising stacked dies. The simulation results indicated that byoverlapping high-power-consuming circuits using the heat dissipatingring, the operation temperature of the high-power-circuits portion of asample logic die is reduced from 90.5° C. in conventional packages to72.3° C. in accordance with embodiments. Furthermore, the operationtemperature of the low-power-circuits portion of the sample logic die isreduced from 77.9° C. in conventional packages to 72.1° C. in accordancewith embodiments. Therefore, by adopting the heat dissipating schemes ofthe embodiments of the present disclosure, not only the operationtemperatures of the packages are reduced, the hot spots are alsoeliminated.

In accordance with some embodiments, a package includes a first die anda second die underlying the first die and in a same first die stack asthe first die. The second die includes a first portion overlapped by thefirst die, and a second portion not overlapped by the first die. A firstTIM is over and contacting a top surface of the first die. A heatdissipating lid has a first bottom surface contacting the first TIM. Asecond TIM is over and contacting the second portion of the second die.A heat dissipating ring is over and contacting the second TIM.

In accordance with other embodiments, a package includes a die stackincluding a plurality of dies, and a die underlying and bonded to thedie stack. The die includes a first portion overlapped by the die stack,and a second portion not overlapped by the die stack. A first TIM isover and contacting a top surface of the die stack. A heat dissipatinglid has a first portion over and contacting the first TIM, and a secondportion overlapping the second portion of the die. A second TIM is overand contacting the second portion of the die. A heat dissipating ringhas an extension portion, wherein the extension portion is overlapped bythe second portion of the heat dissipating lid. The extension portion ofthe heat dissipating ring further includes a bottom surface contactingthe second TIM.

In accordance with yet other embodiments, a package includes a die stackincluding a plurality of dies, and a die underlying and bonded to thedie stack. The die includes a first portion overlapped by the die stack,and a second portion not overlapped by the die stack. A first TIM isover and contacting a top surface of the die stack. A second TIM is overand contacting the second portion of the die. A heat dissipating lid hasa first bottom surface contacting the first TIM, and a second bottomsurface contacting the second TIM.

Although the embodiments and their advantages have been described indetail, it should be understood that various changes, substitutions andalterations can be made herein without departing from the spirit andscope of the embodiments as defined by the appended claims. Moreover,the scope of the present application is not intended to be limited tothe particular embodiments of the process, machine, manufacture, andcomposition of matter, means, methods and steps described in thespecification. As one of ordinary skill in the art will readilyappreciate from the disclosure, processes, machines, manufacture,compositions of matter, means, methods, or steps, presently existing orlater to be developed, that perform substantially the same function orachieve substantially the same result as the corresponding embodimentsdescribed herein may be utilized according to the disclosure.Accordingly, the appended claims are intended to include within theirscope such processes, machines, manufacture, compositions of matter,means, methods, or steps. In addition, each claim constitutes a separateembodiment, and the combination of various claims and embodiments arewithin the scope of the disclosure.

What is claimed is:
 1. A package comprising: a first die; a second dieunderlying the first die and in a same first die stack as the first die,wherein the second die comprises: a first portion overlapped by thefirst die; and a second portion extending laterally beyond a respectiveedge of the first die; a first Thermal Interface Material (TIM) over andcontacting a top surface of the first die; a heat dissipating lidcomprising a first bottom surface contacting the first TIM; a second TIMover and contacting the second portion of the second die; and a heatdissipating ring comprising a portion over and contacting the secondTIM, wherein the heat dissipating lid and the heat dissipating ring arediscrete components, and at least one of the heat dissipating lid or theheat dissipating ring comprises a plurality of fins and a plurality ofrecesses separating the plurality of fins from each other.
 2. Thepackage of claim 1, wherein the heat dissipating lid comprises theplurality of fins and the plurality of recesses.
 3. The package of claim2 further comprising an adhesive film, wherein a bottom surface of theheat dissipating lid and a top surface of the heat dissipating ring areadhered to opposite surfaces of the adhesive film.
 4. The package ofclaim 3, wherein one of the plurality of recesses extends to a levellower than the adhesive film.
 5. The package of claim 1, wherein topsurfaces of the heat dissipating lid and the heat dissipating ring arecoplanar with each other.
 6. The package of claim 1, wherein the heatdissipating lid comprises the plurality of recesses, and the pluralityof recesses comprises: a first plurality of recesses extending to afirst depth into the heat dissipating lid; and a second plurality ofrecesses extending to a second depth into the heat dissipating lid,wherein the second depth is greater than the first depth.
 7. The packageof claim 6, wherein the first plurality of recesses overlaps the heatdissipating ring.
 8. The package of claim 1, wherein the heatdissipating ring comprises the plurality of recesses, and the pluralityof recesses comprises: a first plurality of recesses extending to afirst depth into the heat dissipating ring; and a second plurality ofrecesses extending to a second depth into the heat dissipating ring,wherein the second depth is greater than the first depth.
 9. A packagecomprising: a die stack comprising a plurality of dies; a die underlyingand bonded to the die stack, wherein the die comprises: a first portionoverlapped by the die stack; and a second portion not overlapped by thedie stack; a first Thermal Interface Material (TIM) over and contactinga top surface of the die stack; a heat dissipating lid; a second TIMover and contacting the second portion of the die; and a heatdissipating ring having a portion encircling the heat dissipating lid,wherein a top surface of the heat dissipating lid and a top surface ofthe heat dissipating ring are coplanar with each other, and both theheat dissipating lid and the heat dissipating ring comprise fins andrecesses separating the fins from each other.
 10. The package of claim 9further comprising an adhesive film, wherein the heat dissipating lidcomprises: a first portion over and contacting the first TIM; and asecond portion overlapping the second portion of the die, wherein thesecond portion of the heat dissipating lid is joined to a top surface ofthe heat dissipating ring through the adhesive film.
 11. The package ofclaim 10, wherein the recesses in the heat dissipating lid comprises: afirst plurality of recesses overlapping the adhesive film; and a secondplurality of recesses vertically misaligned from, and extending to alevel lower than, the adhesive film.
 12. The package of claim 9, whereinthe die comprises: a high-power-consuming circuit; and alow-power-consuming circuit consuming less power than thehigh-power-consuming circuit, wherein the high-power-consuming circuitis at least partially located in the second portion of the die.
 13. Thepackage of claim 9, wherein the heat dissipating lid and the heatdissipating ring are physically discrete components.
 14. The package ofclaim 9 further comprising: a package substrate underlying and bonded tothe die; and an additional adhesive film adhering a bottom surface ofthe heat dissipating ring to the package substrate.
 15. The package ofclaim 14, wherein the recesses in the heat dissipating ring comprises: afirst plurality of recesses overlapping the additional adhesive film;and a second plurality of recesses vertically misaligned from theadditional adhesive film, wherein the second plurality of recesses isshallower than the first plurality of recesses.
 16. A packagecomprising: a package substrate; a die overlying and bonded to thepackage substrate; a heat dissipating lid overlapping the die; a firstThermal Interface Material (TIM) over and contacting a top surface ofthe die; and a heat dissipating ring encircling the heat dissipatinglid, wherein the heat dissipating ring is joined to the die through thefirst TIM, and the heat dissipating ring comprises first fins and firstrecesses separating the first fins from each other, and bottoms of thefirst recesses are lower than the heat dissipating lid.
 17. The packageof claim 16 further comprising: a second TIM; and a die stack comprisinga plurality of dies, wherein the die stack is over and bonded to thedie, and a bottom surface of the heat dissipating lid is adhered to atop surface of the die stack through the second TIM.
 18. The package ofclaim 17, wherein the heat dissipating lid comprises second fins andsecond recesses separating the second fins from each other, and thesecond recesses comprise: deep recesses overlapping the die stack; andshallow recesses shallower than the deep recesses, wherein the shallowrecesses overlap a portion of the die not overlapped by the die stack.19. The package of claim 17, wherein the die comprises: ahigh-power-consuming circuit; and a low-power-consuming circuitconsuming less power than the high-power-consuming circuit, wherein thehigh-power-consuming circuit is at least partially located in a portionof the die not overlapped by the die stack.
 20. The package of claim 16further comprising an adhesive film contacting a bottom surface of theheat dissipating lid and a top surface of the heat dissipating ring.